Metal oil pan with an integrated oil filter

ABSTRACT

The invention relates to a metal oil pan for engines or transmissions, with an oil filter medium arranged therein, wherein part of the oil pan forms the bottom of an oil filter housing and a plastic half-shell forms a cover of the oil filter housing, and the oil filter medium is arranged between the oil pan and the plastic half-shell, the oil pan having metal rivets at its edge, and the plastic half-shell having bores at its edge, through which the plastic half-shell is fastened to the metal oil pan.

[0001] The invention is directed to a metal oil pan for engines ortransmissions with integrated oil filter which can be operated assuction or pressure oil filter.

[0002] Oil filters are employed in engines and transmissions to purifythe oil used to lubricate the engine or transmission. Various types ofoil filters for engines or transmissions are known from the prior art.In general, they consist of a flat filter housing having twohalf-shells. A disc-shaped or bag-shaped or a folded filter medium isfixed between the two half-shells. Metal screens, paper filters orpolyester filter felts are used as filter media. The filter half-shellsjoined together in an airtight fashion can be made of metal or plastic.

[0003] Conventionally, oil filtration in an engine or in an automatictransmission is effected using filters arranged separately outside theoil pan. To this end, the filter, oil pan seal and oil pan are used assingle components. The oil pan usually is made of metal. Thus,deep-drawn steel or aluminum-magnesium cast alloys are used in general.

[0004] The oil filters must be arranged so as to meet specificrequirements. Thus, they have to be accessible as easily as possible andreplaceable or removable in a simple fashion during maintenance works.In most of the cases, this is achieved by arranging the oil filters soas to protrude from the engine level. In order to prevent the requiredspace for the oil filter from becoming too large in size, the oil filtersize in motor oil filters is severely restricted. The oil filterstherefore have a small filter surface and as a result, they undergofouling relatively quickly and require frequent replacement. In theevent of automatic transmissions, however, filter systems designed asservice life filters are already available.

[0005] In general, the space available within the engine compartment innew constructions of engines and transmissions is highly limited. Bulkyconstructions, particularly oil filter constructions protruding from theengine level are undesirable and disadvantageous.

[0006] To avoid these drawbacks, oil filters integrated in the oil panof engines or transmissions have been developed recently. Suchintegration offers the advantage of allowing rational utilization of thespace available in the oil pan which otherwise merely is intended toreceive oil not being used in the engine or transmission circulation.Thus, the German patent 197 35 444.0 describes correspondingarrangements of oil filter inserts in an oil pan. DE 197 35 445.9describes the integration of a suction oil filter in an oil pan made ofplastic.

[0007] However, the integration of oil filters in oil pans involves aproblem in that oil pans frequently are made of metal, while filterinserts generally consist of plastic material. For trouble-free functionof the oil filter in the oil pan, it is indispensable that the jointbetween filter insert and oil pan remains durably tight, enduring evenover ranges of high temperature. One should keep in mind thattemperature stress in the motor vehicle may range between 40 and +100°C., depending on the user's geographic location and temperature of theoil. As a result of the dissimilar physical properties of metal andplastic materials, it is highly problematic to join these materials soas to create an oil pan with an oil filter insert that would ensure oilfiltration throughout the service life with perfect function andtightness.

[0008] The technical object of the invention was therefore to provide ametal oil pan for engines or transmissions, with an oil filter mediumarranged therein, which oil pan avoids the above-mentioned drawbacks,specifically enabling long-term and trouble-free oil filtration, andalso has sufficient and permanent tightness even under major temperaturefluctuations.

[0009] The above technical object is accomplished by means of a metaloil pan for engines or transmissions, with an oil filter medium arrangedtherein, wherein part of the oil pan forms the bottom of an oil filterhousing and a plastic half-shell forms a cover of the oil filterhousing, and the oil filter medium is arranged between the oil pan andthe plastic half-shell, the oil pan having metal rivets at its edge, andthe plastic half-shell having bores at its edge, through which theplastic half-shell is fastened to the metal oil pan. Hereinafter, theoil filter medium is understood to be the unit comprised of the oilfilter insert with the oil filter material attached thereto.

[0010] In an alternative embodiment, the plastic half-shell has ametallic frame, through which the plastic half-shell is joined to themetal oil pan via electromechanical joining. In a preferred fashion,this is effected by punctual welding together the metallic frame withthe frame of the metal oil pan. In a particularly preferred fashion, themetallic frame consists of copper.

[0011] In a preferred embodiment, the oil filter medium is arranged in asupport frame which preferably consists of plastic. In a preferredfashion, the support frame is joined to the plastic half-shell. Usually,the support frame consisting of plastic is extruded around the filtermedium which subsequently is joined to the plastic half-shell likewiseconsisting of plastic.

[0012] In another preferred embodiment, support frame, plastichalf-shell and oil pan are beaded together at their edges.

[0013] It is also preferred to use copper-clad weld-on tubular rivets asmetal rivets. The weld-on tubular rivets are situated at the outer edgeof the oil pan or arranged at the bottom of the oil pan. The plastichalf-shell has bores at its edge, so that the plastic half-shell can beplaced on a particular area of the oil pan, and the metal rivets on theoil pan are passed through the bores. This is followed by welding therivets, so as to make a firm joint between the oil pan and the plastichalf-shell. It is also preferred to insert seals between oil pan andplastic half-shell, which seals preferably are attached to the supportframe. In a preferred fashion, profile gaskets, flat gaskets andtoroidal sealing rings are used as seals.

[0014] The rivets arranged on the oil pan can be arranged in any number,shape and position, depending on the shape of the plastic half-shellused and on the respective oil pan.

[0015] Furthermore, it is preferred to have flow ribs and/or supportribs molded in the plastic half-shell and/or on the support frame, whichsupport the filter medium and the plastic half-shell on the oil pan.Moreover, spacer domes arranged on the plastic half-shell can be presentto support the plastic half-shell on the metal oil pan, said spacerdomes penetrating the filter medium or being firmly connected with same.

[0016] The oil pan according to the invention is produced via thefollowing steps:

[0017] Initially, plastic material is extruded around the filter mediumso as to form a support frame for the filter medium. The support framethen is joined with the is plastic half-shell. The support frame isprovided with a sealing medium. The plastic half-shell then is placed onthe particular area of the metal oil pan provided with the weld-ontubular rivets, so that the rivets at the edge of the correspondingparticular area of the metal oil pan pass through the bores arranged atthe edge of the plastic half-shell. The rivets then are welded on, sothat the plastic half-shell is firmly joined to the particular area ofthe oil pan.

[0018] The oil pan of the invention with integrated oil filter mediumcan be used for suction or pressure oil filtration.

[0019] Such integration of the oil filter housing in the oil filter panis advantageous in that separate arrangement of the oil filter housingin the engine compartment is no longer required, thereby providing morespace for other engine components in the engine compartment.Furthermore, non-utilized space in the oil pan is made useful by suchintegration of the oil filter housing.

[0020] The above-described joint between plastic half-shell and metaloil pan via metal rivets or by means of a metallic frame which is weldedpermits firm and permanent joining of the metal oil pan and the plastichalf-shell. In this way, a compact assembly is formed, enablingfunctional and stable oil filtration throughout the service life of thevehicle, so that frequent replacement of the oil filter is not required.It is even possible to design the filter surface in such a way thatreplacement of the filter is no longer necessary during the averageservice life of the respective vehicle.

[0021] Another advantage of the invention is that the number of requiredcomponents is substantially minimized, resulting in a reduction of theoverall weight of the vehicle and in a substantial facilitation and costreduction of the production. According to the invention, a singlecomponent including the oil pan and oil filter medium is used, while inthe prior art not only the oil pan but also the oil filter must beinstalled in the vehicle as separate components.

[0022] The subject of the invention will be illustrated in more detailin the figures below.

[0023] The FIGS. 1 to 4 and 7 show diverse cross-sectional views ofvarious embodiments of the oil pan according to the invention. FIGS. 5and 6 show top views of the oil pan according to the invention.

[0024]FIG. 1 shows a cross-sectional view. Numeral 1 denotes the oil panmade of metal, numeral 2 denotes the plastic half-shell fastened to theoil pan by means of metal rivets. The oil filter medium is arrangedbetween the plastic half-shell and the bottom of the metal oil pan. Bymeans of such metal riveting, the filter material is beaded directlywith the oil pan and the plastic half-shell at the edges thereof. In apreferred embodiment, a seal not shown in this illustration is providedbetween plastic half-shell and metal oil pan.

[0025] Numeral 8 denotes a support of the plastic half-shell at thebottom of the oil pan. The oil inlet in this embodiment is indicated bynumeral 7 and is situated at the right side of the oil filter beneaththe oil filter medium. The oil flows from the bottom upwardly throughthe filter medium to the oil outlet. Furthermore, support ribs 10 areprovided, ensuring stable positioning of the oil filter medium.

[0026] Numeral 9 denotes the beading between oil pan, plastic half-shelland filter medium.

[0027]FIG. 2 describes a cross-sectional view of the oil pan accordingto the invention, which differs from that in FIG. 1 in that the oilflows from the top to the bottom. The oil inlet is denoted with numeral7 and is situated above the filter medium. The oil flows from the topdownwardly through the filter medium and is collected at the bottom ofthe oil pan. The oil outlet nozzle is designed so as to reach the bottomof the oil pan and therefore, it is possible to return the oil fromthere via the oil outlet into the engine or transmission circulation.

[0028] The embodiments in FIGS. 1 and 2, which are characterized by thedifferent directions of oil flow through the filter medium, are usedaccording to the structure and shape of the oil pan employed, and alsofor space-related reasons. In this way, the oil filter insert and thedirection of oil flow can be adapted to the requirements of thepre-molded oil pan in any desired fashion.

[0029] To ensure sufficient tightness of the riveting, sealing elementsor adhesives are preferably used at the edge. In a likewise preferredfashion, the metal rivets have a step arranged at the bottom and/or topend thereof.

[0030]FIG. 3 describes another embodiment of the oil pan according tothe invention. In this embodiment, the filter medium is held in asupport frame. The support frame usually consists of plastic, so thatthe plastic can be extruded around the filter medium. The support framethen is joined to the plastic half-shell, so that direct joining offilter medium and plastic half-shell as in FIGS. 1 and 2 is notnecessary. This is advantageous in that a direct plastic-plastic jointis possible. Furthermore, the area of filter medium available forfiltration is increased by this measure and also, mass production of therespective filter medium is made possible.

[0031] In this embodiment as well, the oil inlet—according to numeral7—is beneath the filter medium, and the oil then is passed through thefilter medium and upwardly to the oil outlet. Again, numeral 10 denotessupport ribs ensuring stable positioning of the filter medium.

[0032]FIG. 4 shows another embodiment of the oil pan according to theinvention. In FIG. 4, the support frame is not joined to the plastichalf-shell but beaded directly with the metal oil pan and plastichalf-shell via an elongation. This measure likewise ensures hightightness of the joint between oil pan and plastic half-shell.

[0033]FIG. 5 shows a top view on the oil pan according to the inventionwith the oil filter insert which has bores according to numeral 5.Numeral 7 denotes the oil inlet, and numeral 6 denotes the oil outlet.

[0034]FIG. 6 shows two top views with different arrangements of the oilfilter medium 3 in the oil pan 1. In this case, fixing plates 12 aremolded on the oil filter insert, which are capable of engaging with theweld-on tubular rivets 5 by placing and positioning, thereby firmlypositioning the filter in the oil pan with respect to all directions.The holding plate 11 designed as a clip is capable of both radial andaxial securing, thus ensuring a firm joint of the oil filter insert inthe oil pan.

[0035]FIG. 7 shows a corresponding cross-sectional view of theembodiment in accordance with FIG. 6. Numeral 6 denotes the oil outlet.Numeral 4 denotes the metal rivets affixed to the bottom of oil pan 1.The oil filter insert has the fixing plates 12 arranged thereon, whichengage with the weld-on tubular rivets 4, thereby creating a firm jointbetween oil filter insert and oil pan.

[0036] This arrangement achieves the following advantages. Oil pan andfilter constitute a firm unit, and the filter is held properly duringassembly and disassembly. It is not necessary to secure the filter tothe transmission housing. The filter can be disassembled, i.e., can bereplaced as well. Furthermore, no vibration noise is generated as aresult of the firm joint between filter insert and oil pan, unlike inthose variants where the filter rests loosely on the oil pan.

[0037] In general, supporting the plastic half-shell versus the metalpan is effected by means of a single component welded firmly and tightlynear the filter medium, by means of interconnected spacer domes, or bymeans of a plastic frame having spacer domes and/or flow ribs moldedthereon. Instead of the weld-on tubular rivets, a metallic framedeposited or embedded in the plastic half-shell can be used, protrudingfrom the plastic half-shell at well-defined positions so as to enablepunctual electromechanical joining to the metal oil pan.

[0038] The oil can be conducted from the bottom through the filter bymeans of an oil intake opening molded on the metal oil pan andappropriate recesses on the plastic half-shell and/or the filter supportframe, upwardly through the filter medium to the plastic half-shell,through an outlet seal molded on the plastic half-shell to the suctionside of the oil pump. Another possible oil flow would be that the oil ispassed from the top through the plastic half-shell, through the filtermedium above the metal oil pan, and then through a pipe or channelextending from the suction side of the pump down to the lower filtercompartment, through which the oil can be sucked off.

[0039] Key to the drawing  1 Oil pan  2 Plastic half-shell  3 Oil filtermedium as oil filter insert  4 Metal rivets  5 Bores  6 Oil outlet  7Oil inlet  8 Support plastic half-shell/bottom of oil pan  9 Beading ofoil pan/plastic half-shell/filter medium  9a Beading of oil pan/plastichalf-shell  9b Beading of oil pan/plastic half-shell/support frame 10Support ribs 11 Support frame for oil filter medium 12 Fixing plate

1. A metal oil pan (1) for engines or transmissions, with an oil filtermedium (3) arranged therein, wherein part of the oil pan (1) forms thebottom of an oil filter housing and a plastic half-shell (2) forms acover of the oil filter housing, and the oil filter medium (3) isarranged between the oil pan (1) and the plastic half-shell (2), the oilpan (1) having metal rivets (4) at its edge, and the plastic half-shell(2) having bores (5) at its edge, through which the plastic half-shell(2) is fastened to the metal oil pan (1).
 2. A metal oil pan (1) forengines or transmissions, with an oil filter medium (3) arrangedtherein, wherein part of the oil pan (1) forms the bottom of an oilfilter housing and a plastic half-shell (2) forms a cover of the oilfilter housing, and the oil filter medium (3) is arranged between theoil pan (1) and the plastic half-shell (2), the plastic half-shell (2)having a metallic frame, through which the plastic half-shell (2) isjoined to the metal oil pan (1) via electromechanical joining.
 3. Theoil pan according to claim 1 or 2, characterized in that the oil filtermedium (3) is arranged in a support frame (11).
 4. The oil pan accordingto claims 1 to 3, characterized in that the support frame (11) is joinedto the plastic half shell (2).
 5. The oil pan according to claims 1 to4, characterized in that the support frame (11), the plastic half-shell(2) and the oil pan (1) are beaded together.
 6. The oil pan according toclaims 1 to 5, characterized in that the metal rivets (4) arecopper-clad weld-on tubular rivets.
 7. The oil pan according to claims 1to 6, characterized in that the support frame (II) has profile gaskets,flat gaskets and toroidal sealing rings arranged thereon.
 8. The oil panaccording to claims 1 to 7, characterized in that the rivets (4) arearranged in any number, shape and position at the outer edge of themetal oil pan (1).
 9. The oil pan according to claims 1 to 8,characterized in that flow ribs and/or support ribs (10) are molded inthe plastic half-shell (2) and/or on the support frame (11).
 10. The oilpan according to claims 1 to 9, characterized in that the support (8) ofthe plastic half-shell (2) on the metal oil pan (1) is accomplished bymeans of spacer domes (8) arranged on the plastic half-shell, saidspacer domes penetrating the filter medium or being firmly joined tosame.
 11. The oil pan according to claims 1 to 10, characterized in thatfixing plates (12) for positioning the oil filter insert in the oil panare molded on the oil filter insert (3).
 12. A process for producing theoil pan according to claims 1 to 11, characterized by the followingsteps: plastic material is extruded around the filter medium so as toform a support frame for the filter medium; the support frame is joinedto the plastic half-shell; the plastic half-shell is provided with asealing medium; the metal oil pan is provided with weld-on tubularrivets, said weld-on tubular rivets being positioned in accordance withthe contour profile of the plastic half-shell; the plastic half-shellhaving bores arranged at the edge thereof is placed on the metal oilpan, so that the rivets pass through the bores; electromechanicaljoining of the plastic half-shell and the oil pan by riveting.